sergey.alexandrov
Товарищи! Чем Root Mean Square отличается от Root Mean Quad? What is the difference between these?
13 Thg 02 2012 17:17
Câu trả lời · 4
1
Root Mean Square = square root {Σ of the squares ( X with exponent 2) / number of data} Root Mean Quad = fourth root {Σ of X with exponent 4/número data} Σ = addition
14 tháng 2 năm 2012
"The discomfort of standing people experiencing steady-state vibration can be predicted from the root-mean-square (rms) of the frequency-weighted acceleration, but alternative methods are advocated for evaluating motions containing transients. Using the method of magnitude estimation, 20 standing subjects estimated the discomfort caused by octave-bandwidth random vibrations at two centre frequencies (1 and 8 Hz) in each of three directions (fore-and-aft, lateral and vertical). For motions having seven different crest factors (i.e. the ratio of the peak to the rms value), the vibration magnitude required for similar discomfort, and a method predicting this equivalence, were determined. The rms method (with an exponent of 2) and the root-mean-quad method (exponent of 4) tended to, respectively, underestimate and overestimate the discomfort of high-crest factor motions. The optimum evaluation method had an exponent of about 3.0 for 1-Hz motions and 3.5 for 8-Hz motions. Current standards do not provide reliable indications of when vibration discomfort can be predicted by an rms measure. STATEMENT OF RELEVANCE: Current standards recommend alternatives to the root-mean-square method (exponent of 2.0) for predicting the discomfort caused by transient vibration. The alternatives include the root-mean-quad or vibration dose value (exponent of 4.0) and peak values. An exponent of 2.0 underestimates, but an exponent of 4.0 slightly overestimates, the discomfort of transients experienced by standing people. Peak values are not appropriate." http://www.ncbi.nlm.nih.gov/pubmed/22103730 http://en.wikipedia.org/wiki/Root_mean_square I have the impression that RMS is more general than RMQ.
13 tháng 2 năm 2012
Bạn vẫn không tìm thấy được các câu trả lời cho mình?
Hãy viết xuống các câu hỏi của bạn và để cho người bản xứ giúp bạn!
sergey.alexandrov
Kỹ năng ngôn ngữ
Tiếng Anh, Tiếng Pháp, Tiếng Đức, Tiếng Ý, Tiếng Na Uy, Tiếng Bồ Đào Nha, Tiếng Nga, Tiếng Tây Ban Nha
Ngôn ngữ đang học
Tiếng Pháp, Tiếng Ý, Tiếng Bồ Đào Nha, Tiếng Tây Ban Nha